import gmsh
import sys


gmsh.initialize()

gmsh.model.add("mover")

def four_square_mag(height, offset):
    volumes = {
        "magnet-N": [
            gmsh.model.occ.addBox(0, 0, 0, offset, offset, height),
            gmsh.model.occ.addBox(0, 0, 0, -offset, -offset, height),
        ],
        "magnet-S": [
            gmsh.model.occ.addBox(0, 0, 0, -offset, offset, height),
            gmsh.model.occ.addBox(0, 0, 0, offset, -offset, height),
        ]
    }
    return volumes



def add_iron(base, offset, height, radius):
    base["iron"] = [
            gmsh.model.occ.add_cylinder(0, 0, offset, 0, 0, height, radius),
    ]
    return base

# We can log all messages for further processing with:
gmsh.logger.start()

# air volume
air_orig = gmsh.model.occ.addSphere(0, 0, 0, 100)

volumes = four_square_mag(3, 12.5)

#add a back iron
volumes = add_iron(volumes, 3, 3, 30.1776/2)



all_vols = []
for name, tags in volumes.items():
    all_vols += [(3, x) for x in tags]

# use fragment to stich it all together
ov, ovv = gmsh.model.occ.fragment([(3, air_orig)], all_vols)


gmsh.model.occ.synchronize()

# assign physical groups using dictionary
for name, tags in volumes.items():
    gmsh.model.addPhysicalGroup(3, tags, name=name)

# air phys group
gmsh.model.addPhysicalGroup(3, [ov[-1][1]], name="air")


#mesh size for air
gmsh.model.mesh.setSize(gmsh.model.getBoundary([(3, ov[-1][1])], False, False, True),
                        10)

#mesh size for inner objects
gmsh.model.mesh.setSize(gmsh.model.getBoundary(all_vols, False, False, True),
                        0.5)

# gmsh.option.setNumber("Mesh.MeshSizeFromCurvature", 120)

gmsh.model.mesh.generate(3)

gmsh.write("mover.msh")

# Inspect the log:
log = gmsh.logger.get()
print("Logger has recorded " + str(len(log)) + " lines")
gmsh.logger.stop()

# Launch the GUI to see the results:
if '-nopopup' not in sys.argv:
    gmsh.fltk.run()

gmsh.finalize()